IJREAM-Approved By

Home , Pongamia oil

International Journal for Research in Engineering Application & Management (IJREAM) ISSN : 2454-9150 Vol-04, Issue-08, Nov 2018

Transesterified Pongamia oil for Liquid Insulation Application

Ann Pamla Cruze, Engineering Officer,Central Power Research Institute, Bengaluru, India, [email protected] K.S.Lokesh, Prof & Registrar, JSS Science and Technology University, Mysuru,India, [email protected]

Abstract : Transformers and other high power rated electrical equipments use insulating oil. These insulating oil is used as insulant and coolant in transformers and other such allied equipments. Presently, mineral oils are widely used in transformers and electrical equipments as insulating oils. These mineral oils are derivative from crude petroleum and biodegradable upto 50%. Hence vegetable oils are experimented to be used as alternative to mineral insulating oils. This paper investigates the performance of critical characteristics of crude pongamia oil. This is non- edible oil is extracted from pongamia nseeds. It is a source of sustainable and environment-friendly insulating oil. Crude pongamia oil is processed by transesterification methods to improve the performance properties such as color and appearance, density, viscosity, pour point, water content, acidity and electrical properties for better insulation efficiency. Results indicate that crude pongamia processed by transesterification shows improvement in all properties but decrease in flash and fire point values. Further processed oils are evaluated for rapid thermo-oxidative conditioning to evaluate the oxidation stability of oils for a duration of 48 hours and 96 hours.

Keywords — Pongamia oil, Transesterification, Mineral insulating oil , Oxidation stability

I. INTRODUCTION seeds, sunflower, corn, soybeans, grape seeds, sesame etc [11-14]. Most of the oils are edible in nature and processed High power rated electrical equipments such as by transesterification. Hence the experiments are carried transformers, switchgears, potential transformers, capacitors out on crude pongamia oil (CPO) which is non-edible and other such equipment in the power system use vegetable oil. CPO is abundantly available in southern insulating liquid. The performance of these transformers region of Asia [15-16]. Results indicate that CPO shows depend on the working condition of its insulation system. better performance with respect to electric strength flash Hence, insulation is the most vital part in the transformer. point and fire point. Properties like acidity, dissipation This insulation system consists of insulating oil and kraft factor, resistivity, density, viscosity pour point and paper. Insulating oil contributes to the overall performance oxidation stability needs modification. Hence the CPO is of the transformer [1-3]. In transformer, the energy is lost in processed by transesterification (TE-PO) [17-19]. The the form of heat due to leakages of flux or eddy current critical properties are also evaluated on the processed which in turn rises the temperature of the windings. So this MIO,CPO & TE-PO. During use in the transformer the heat is absorbed by the insulating oil and is transmitted to properties of insulating oil tend to deteriorate mainly due the cooler outer surface. Insulating oil provides an electrical to thermo-oxidation [20-29]. Hence the oils were insulation due to its high dielectric property. Mineral oil conditioned for rapid thermo oxidative ageing to evaluate serve as a extensive insulating oil in electrical equipment. their long term performance. Mineral oil has excellent electrical and cooling properties [4-5]. However mineral oil has relatively low flash point This paper investigates on the critical characteristics of which constitute for high risk of fire and explosion and less Pongamia oil as a new insulating oil. The results were biodegradability [6-7]. compared to performance of mineral insulating oil [16]. From the environmental standpoint, the vegetable oil II. PROCEDURES AND EXPERIMENTS provide an potential alternative sources to mineral oil [8- A. Materials 10]. It provides better environmental safety, low risk of fire and enhance the insulation life. In this regard, most of the 1.0 Samples: The Mineral insulating oil is purchased researchers have worked on vegetable oils from rape from M/s Raj Petro Specialties Pvt Ltd. Chennai and base

522 | IJREAMV04I0844075 DOI : 10.18231/2454-9150.2018.1134 © 2018, IJREAM All Rights Reserved. International Journal for Research in Engineering Application & Management (IJREAM) ISSN : 2454-9150 Vol-04, Issue-08, Nov 2018 or crude PO purchased from Gandhi Krishi Vignana database of information is available to enable interpretation Kendra, Bangalore. of changes to its characteristics and thus predict the possible malfunction of a transformer. IEC 60422 is a good tool to 2.0 Chemicals used: methanol, propanol, potassium evaluate the quality of insulating oils in operational hydroxide (KOH) n-heptane, toluene,(make : Merck) transformers. 3.0 MINERAL INSULATING OIL(MIO) 5.0 CRUDE PONGAMIA OIL(CPO) Mineral oil is a hydrocarbon mixture derived from the Crude Pongamia oil is extracted from the seeds/ pods of intermediate distillate which is obtained by processing the Pongamia tree. This species is a plant of Leguminosea crude petroleum. During the present few decades mineral family found in Eastern Himalaya, Sri lanka and southern oil based insulating oils are the most popular insulating India liquid because of its abundance, satisfying the properties of an ideal transformer oil. Hence it is used for all types of Chemical composition of pongamia oil insulating liquid filled transformers of all power rating and The seeds of Pongamia oil tree yield an essential oil, It has other such electrical apparatus [31]. a high content of triglycerides, and its disagreeable taste and 4.0 Chemical composition odour are due to bitter flavonoid This combined with variances in soil and weather can change the specific Mineral oil is a transparent, colorless liquid composed composition of Pongamia oil. Typically Pongamia oil is mainly of various types of hydrocarbons, comprising of composed of the following fatty acids. straight chain alkanes, branched alkanes, cyclic paraffins and aromatic hydrocarbons. There are two principal types of mineral oil used for transformers, produced as a result of different oil refining processes: Paraffinic oil is derived from crude oil containing substantial quantities of naturally occurring n-paraffin.

Paraffinic oil has a relatively high pour point and may Fig 1: Pongamia tree Fig 2: Pods of Pongamia require the inclusion of additives to reduce the pour point. Naphthenic oil is derived from crude oil containing a very low level (or none) of naturally occurring n-paraffins. Naphthenic oil has a low pour point and requires no additives to reduce the pour point. Naphthenic oil provides better viscosity characteristics and longer life expectancy. Naphthenic oil has more polar characteristics than paraffinic oil. Fig 3: Pods of Pongamia Fig 4: Seeds of Pongamia Transformer oils contain inhibitors which delay the Table-1 : Typical fatty acid composition of pongamia oil oxidation of oil. These inhibitors might be natural, as occur in uninhibited mineral oils, or synthetic and added, as in Percentage Nomenclature Fatty acid inhibited oils. 3.7% – 7.9% C16:0 Palmitic Uninhibited oils must be free of additives, either natural or 2.4% – 8.9% C18:0 Stearic synthetic, which are used to improve oxidation stability. 44.5% – 71.3% C18:1 Oleic This includes but is not limited to 2,6 di-tertiary-butyl 10.8% – 18.3% C18:2 Linoleic phenol, 2,6 ditertiary-butyl paracresol, or metal deactivators 2.60% C18:3 Linolenic such as benzotriazole and its derivatives. However in the 2.2% – 4.7% C20:0 Arachidic US, the IEEE accept that < 0.08% inhibitor can be classified as uninhibited. 9.5% – 12.4% C20:1 Eicosenoic 4.2% – 5.3% C22:0 Behenic Inhibited oils are insulating oils which have been 1.1% – 3.5% C24:0 Lignoceric supplemented with either 2,6 ditertiary-butyl. phenol or 2,6 ditertiary-butyl paracresol or any other specified and acceptable oxidation inhibitor. New mineral oils are Uses: Parts of Pongamia tree is used as tooth brush & produced to be in accordance with the IEC 60296. Since in manufacture of soaps. Pongamia oil is not been used for mineral oil has been used for such a long time, a large cooking because of its bitter taste and irritable odour.

523 | IJREAMV04I0844075 DOI : 10.18231/2454-9150.2018.1134 © 2018, IJREAM All Rights Reserved. International Journal for Research in Engineering Application & Management (IJREAM) ISSN : 2454-9150 Vol-04, Issue-08, Nov 2018

Leaves are used as fodder and green manure. Medical use include use of Roots of Pongamia seeds are used in treatment of ulcers and also for cleaning teeth and strengthening gums.(Pong2). The kernel is grinded with black pepper and given malarial fever. Flowers are used in diabetes internally and externally in alopecia. The Pongamia seeds are used with camphor help to check diseases like scabies, eczema, ringworm infestation etc. The paste of leaves is applied on wounds helps to relieve pain and swelling of the wounds. In chronic sinusitis powder of leaves of karanja plant taken through nose gives relief. Applying mash of pulp of karanja flowers on head helps to check alopecia. Ghee prepared with bark of Fig.5 processing of pongamia oil karanja is useful in diseases like syphilis and gonorrhea. Pongamia oil is also used on skin to keep away the insects and other microbes from the surface. anti-parasitic, wound healing and analgesic properties The extracts are also used as insecticide and anti microbialial, skin diseases for itching and as antiseptic and antifungal. The oil mixed with neem, guduchi and arishtak,karanja helps to check skin diseases. Bath with leaves boiled in water is useful in arthritis. Its use is indicated in piles, tumors, worm and wounds. Its use has also been indicated in checking obesity. On the other side the parts of the Pongamia oil is used in treatment of circulatory, respiratory, digestive, urinary disorders. Fig.6. Samples of mineral oil and pongamia oil Transesterification of pongamia oil (TE-PO ) C) The PO is evaluated for the properties listed in the specification standard IEC 62770 [30-32], which takes The crude PO does not possess all the required reference to the sub standards for the test methods as characteristics of an ideal insulating oil. Hence, the PO mentioned in the subsequent test methods. Further, the aged need to be processed to improve its performance. Two samples are tested for physiochemical properties and methods have been experimented like transesterification. electrical properties. Transesterification is a process to convert triglycerides to fatty acids methyl esters. Transesterification of PO is 1) Breakdown voltage (Electric Strength): Breakdown voltage is measured in accordance with IEC: 60156 using carried out by the reaction of PO and methanol (CH3OH) in the volume ratio of 1:6, with KOH as base catalyst, The Electric Strength apparatus [33]. The oil sample, contained process is shown in the flow chart. The process comprises in a specified container is subjected to an increasing AC of two stages as referred in fig 5. first is reaction stage and electrical field, by means of a constant rate of voltage, until the second conditioning stage is common procedure to breakdown occurs. remove the residual acids, water soluble, moisture, 2) Dielectric dissipation factor and dielectric constant: sediments dissolved moisture and suspended particles. The Dielectric Dissipation Factor (DDF) and Dielectric constant treatment process shown in figure 5 and the finished (DC) is measured in accordance with IEC:60247 [34] at products are shown in figure 6. 100ºC using dissipation factor, dielectric constant, specific resistance equipment, 3) Volume resistivity: Volume resistivity is measured by following the test method mentioned in IEC:60247 [34], by using Dissipation factor, Dielectric constant, Specific Resistance equipment. Measurements were made at 500V DC/2mm 4) Density: Density is measured as per ISO:3675 [35], using hydrometer, by suspending the hydrometer into the oil samples. Hydrometer readings are obtained at convenient

524 | IJREAMV04I0844075 DOI : 10.18231/2454-9150.2018.1134 © 2018, IJREAM All Rights Reserved. International Journal for Research in Engineering Application & Management (IJREAM) ISSN : 2454-9150 Vol-04, Issue-08, Nov 2018 temperatures with readings of density hydrometer. and crude pongamia oil is given in table 2. The table also shows the acceptable limits as per the specification 5) Kinematic Viscosity: Viscosity is obtained by measuring standard IEC 62770. The results of crude pongamia oil is the time for a fixed volume of liquid to flow under gravity compared to that of mineral oil to understand the through a calibrated glass capillary Oswald U tube performance level. viscometer Constant temperature bath. Viscosity is measured in accordance with ISO:3104 at 40ºC [36]. Also the results of crude pongamia oil is compared to the acceptance limits as per the specification standard IEC 6) Pour point: pour point is measured according to standard :62770. Crude pongamia oil (CPO) does meet the ISO:3106 [37] by using automatic pour point apparatus. specification in density, viscosity, electric strength, flash 7) Interfacial tension: The interfacial tension is measured in point and fire point but not for pour point, acidity, accordance with ASTM D 971[38] by using Interfacial dissipation factor. Resistivity value for CPO is very low tensiometer. when compared to that of the mineral oil. Hence the CPO 8) Water content: Water content is measured as per the was processed by transesterification. Transesterification standard IEC:60814[39] using Karl Fischer Moisture meter process help in recombination of ester molecules by by using Karl Fischer Moisture meter. interacting with methane radical. Further the treated oil is washed with hot water to remove the l water soluble such 9) Acidity number: The acidity of insulating oil is measured as methane and acids. At this point the acid content of by the required quantity in milligram of potassium oil is about 2mgKOH/g. After washing the oil is passed Hydroxide (KOH) to entirely neutralize the acidity of a through molecular sieve columns to further reduce acids and specific quantity (in gram) of the oil. Acidity is measured by water content. Repeat the molecular sieve treatment till no titration as per the standard IEC 62021-1-2007[40]. change in acidity is observed. Further to reduce the 10) Flash point and fire point: Flash point and fire point is moisture content to below 200 ppm treat the oil with hot carried out by Cleveland open cup according to standard vacuum filtrations. Transesterified oil (TE-PO) is measured ISO:2592 [41] by Flash and Fire point apparatus. for the essential parameters. Tranesterified oil is further conditioned for oxidation process to measure the 11) Oxidation stability conditioning performance of oxidation stability characteristics.The After the processing treatment the insulating oils viz, MIO, results of oxidized samples are prefixed with OS. The PO,TE-PO are contained for rapid thermo-oxidation performance for CPO, TE-PO and OS-TE-PO, are reaction at accelerated conditions for 48 hrs at 120ºC with compared to the acceptance limits as per IEC 62770 and the bubbling of oxygen using oxidation stability apparatus, as performance of MIO. per the standard IEC 61125 [42].

III. RESULTS AND DISCUSSION The results obtained for the mineral insulating oil (MIO) TABLE 2. Performance of mineral insulating oil and crude pongamia oil

Sl Results of MIO,CPO with acceptance limits as per IEC 62770-2013 No. Characteristics Acceptable limits MIO CPO Test Method 1. Breakdown voltage , kV @25 ºC 30 (min) 34.7 44.1 IEC : 60156-1995 2. Dielectric dissipation factor & 0.2 (max) 0.00050 & 2.032 2.76 & 3.41 IEC : 60247-2004 Dielectric constant @ 90 ºC 3. Volume resistivity, *E12, Under consideration 3000 & 250 0.048 & 0.0050 IEC : 60247-2004 Ohm-cm @ 27 ºC & 90 ºC 4. Density, kg/dm3 @20 ºC 1.00 (max) 0.823 0.931 ISO : 3675-1992 5. Kinematic Viscosity, cSt @40 ºC 50 (max) 12.39 47.35 ISO 3104-1994 6. Interfacial tension, mN/m @40 ºC Under consideration 43 35 ISO : 6295-1983 7. Pour point, ºC -10 (max) - 21 12 ISO : 3016-1994 8. Water content, ppm 200 (max) 34 657 IEC : 60814-1997 9. Acid number, mgKOH/g 0.06 (max) 0.0052 10.84 ASTM D 974 -2012 10. Flash point and fire point, ºC 250 & 300, (min) 154 & 162 258 & 316 ISO : 2592-2000 molecules to withstand electrical stress [18]. Figure 7 1) Breakdown voltage: indicates the average breakdown voltage obtained for each Higher value of electric strength indicates the maximum sample. The electric strength value for mineral oil is voltage at which the oil will function as an insulator. 34.7kV. Comparatively, the electric strength of PO is Higher breakdown voltage indicate the capacity of the oil 44.1 kV which is about 20% better when compared to that

525 | IJREAMV04I0844075 DOI : 10.18231/2454-9150.2018.1134 © 2018, IJREAM All Rights Reserved. International Journal for Research in Engineering Application & Management (IJREAM) ISSN : 2454-9150 Vol-04, Issue-08, Nov 2018 of mineral oil. The breakdown voltage for processed oils improvement, due to the removal of conducting molecules. are 74.2kV and 88.8kV, this occurs because of the The resistivity of oxidized oil indicates decreased resistivity removal moisture during the tranesterification processing due to the presence of oxidized products [19]. hence the processed oil shows better electric strength. The TABLE 4 RESISTIVITY pongamia oil after oxidation is cooled to room temperature in a dedicated chamber to avoid the ingress of atmospheric Sl Resistivity x E12, Ohm-cm of MIO , CPO & TE-PO No. o moisture. Hence the oxidized oil indicates higher electric Temp C M I O CPO TE-PO strength of 93.8 kV. Results of CPO,TE-PO and oxidized 1. 27 3000 0.048 0.532 2. 90 250 0.0050 0.056 PO are meeting acceptable limits [43-45]. Temp oC OS - MIO OS-CPO OS-TE-PO 3. 27 45 0.0050 0.067 4. 90 4.78 5.19E-4 0.0068

After oxidation MIO has decrease of 98% for both temperatures ie 27 and 90oC. Whereas CPO has decreased by 88% and TE-PO, has decreased by 87%. This indicates that pongamia oil has better stability compared mineral oil.

4) Density Density of mineral oil is 0.823g/cc. The density of crude pongamia oil is 0.931g/cc which is higher than mineral oil. Fig.7.Breakdown voltage of MIO,CPO and TE-PO density of PO depends on the molecular weight of the fatty acids. The values obtained are indicated in figure 8. 2) Dielectric dissipation factor (DDF) and dielectric constant (DC) : DDF and DC measurements are measured by applying 500V AC at line power frequency of 49.6 Hz. Table 3 shows the values of DDF and DC obtained for The results are shown in table 3. TABLE 3 DDF AND DC

DDF and DC of MO,PO,TE-PO

Sl Sample DDF DC OS- DDF OS-DC No @ 90C @9 @90oC @9 Fig.8.Density of MIO,CPO and TE-PO 1. MIO 0.00050 2.032 0.0011 2.088 Results indicates decrease of density value for TE-PO 2. CPO 2.76 3.41 6.95 3.21 compared to the CPO. This is due to breakdown of long 3. TE--PO 0.067 3.12 0.49 3.24 chain molecules and recombination of ester molecules which is in turn due to the effect of high temperature Low dissipation factor of oil is desired, as it indicates low reaction with methanol solvent and KOH catalyst. Values power factor. Lower DDF is due to absence of ionic of CPO,TE-PO is within the acceptable limits. Density of molecules present in the oil [18-19]. DDF of MIO is better transesterified oil decreases due to the influence of solvent. than CPO. DDF of CPO is beyond the acceptable limits. 5) Kinematic Viscosity(KV) CPO after treatment of transesterification, and series of Viscosity of the insulating oil is very critical property molecular sieve percolation and hot vacuum oil filtered oil from transformer cooling perspective. Viscosities reading (TE-PO), improves DDF by 97% however this is also are showed in figure 9. beyond the permissible limits of IEC 62770. The oxidized oil indicates increased DDF values indicating the deterioration of oil due to the presence of oxidized products [44-45].

3) Resistivity Resistivity measurement is measured at 500V DC/2mm gap in three terminal cell . Results are shown in table 4. MIO has high resistivity value compared to CPO, TE-

PO. Resistivity values of processed oils indicate Fig.9.Kinematic viscosity of MIO,CPO and TE-PO

526 | IJREAMV04I0844075 DOI : 10.18231/2454-9150.2018.1134 © 2018, IJREAM All Rights Reserved. International Journal for Research in Engineering Application & Management (IJREAM) ISSN : 2454-9150 Vol-04, Issue-08, Nov 2018

Lower viscosity is preferred in case of insulating liquid for electrical strength and low dissipation losses. Water content better cooling capability of transformer oil. Viscosity of results are showed in the figure 12. CPO is more compared to that of mineral insulating oil MIO, however it is with the acceptable limits. The higher viscosity value depends on the length of the fatty acids and the combination of cluster of glycerol molecule. Transesterified oil TE-PO decreases viscosity due to breakdown of long chain molecules. Results indicate increase in viscosity of oxidized oil due to the formation of oxidized products.

6) Pour point Pour point of the MIO records to -24ºC, whereas the pour point of CPO is 12ºC. Pour point readings are shown in Fig.12.Water Content of MIO,CPO and TE-PO figure 10. Esterified oil has low pour point of -6ºC due to Water content for a unprocessed CPO is much more than the influence of solvent as methanol solvent has very low mineral oil. Water content is less in processed oils due to pour point of -60ºC. evaporation of water content at elevated temperature and prolonged vacuum filtration for both the processing methods. By vacuum filtration the water content reduces to 400-300 ppm Further on molecular sieve conditioning moisture content is further reduced to 100-200 ppm. Water content is reduced for oxidized oil. This is due to the high temperature conditioning of 120ºC. 9) Acidity Acidic behavior of aqueous any liquids is indicated on the pH scale. Acidic nature of organic liquid is represented by amount of basic substance required to neutralize when the Fig.10.Pour point of MIO,CPO and TE-PO oil is diluted in a solvent mixture. Hence acidity is one of

the important characteristics of liquids. Acids are the aging 7) Interfacial tension by-products of oil in transformers and acids can accelerate Higher value of interfacial tension indicates the absence the aging process. In mineral oil, acidity increases due to of polar components. Interfacial tension for MIO, CPO and thermal and oxidation stresses. The acidity variations are TE-PO, is given in figure 11. shown in table 5. TABLE 5: ACIDITY

Sl No. Acidity of MO,PO,TE-PO Sample Acidity OS-Acidity 1. MIO 0.0052 0.020 2. CPO 10.84 25.48 3. TE-PO 0.36 0.56

As the acidity increases the color of the oil also changes due to the presence of oxidized products such as ketones, aldehydes etc. Acidity of CPO is 10.84 mgKOH/g. TE-PO indicates 0.36 mgKOH/g. The acid number of oxidized Fig.11. Interfacial tension of MIO,CPO and TE-PO CPO increases significantly to 25.48 for oxidized oil. IFT of MIO is 43 mN/m. Comparatively for CPO the Acidity values for CPO,TE-PO is more than acceptable characteristics indicates the value of 35 mN/m. Esterified limits. oil decreases interfacial tension due to influence of 10) Flash point and fire point solvent. IFT of the TE-PO increased due to increase in polar compounds during oxidation process[46]. The flash and fire point of CPO is much higher compared to mineral oil. Figure 13 shows that CPO can withstand 8) Water content higher temperature up to more than 300ºC. Low water content of MIO is necessary to achieve adequate

527 | IJREAMV04I0844075 DOI : 10.18231/2454-9150.2018.1134 © 2018, IJREAM All Rights Reserved. International Journal for Research in Engineering Application & Management (IJREAM) ISSN : 2454-9150 Vol-04, Issue-08, Nov 2018

[6] Atekwana EstellaA., William A. Sauck, Douglas D. Werkema Jr., ―Investigation of geo-electrical signatures at a hydrocarbon contaminated site,‖ Elsevier, Journal of Applied Geophysics 44, pp167–180, 2000. [7] Battersby.N.S., ―The biodegradability and microbial toxicity testing of lubricants,‖ Chemosphere 41, pp. 1011 -1027, 2000. [8] Dibble.J.T, Bartha.R (1979), ―Effect of environmental characteristics on the biodegradation of oil sludge,‖ Applied and Environmental Microbiology, Apr 1979, Vol 37, No4, pp. 729-739. Fig.13.Flash point and Fire point of MIO,CPO and TE-PO [9] Kelly Dumorné, Margie Zorrilla Velazco and Petra Velazco This is due to the bending of the molecular alignment of the Pedroso, ―Analysis of polychlorinated biphenyls treatment fatty acids. Hence pongamia oil can be regarded as fire present in transformers oils,‖ Int. J. Environmental retardant insulating oil. TE-PO decreases the flash point Technology and Management, Inderscience Enterprises and fire point compared to the initial performance. Also the Ltd., vol. 20, Nos. ½, pp10-20, 2017. temperature difference between flash and fire point is [10] Ekpo M.A and Udofia U.S., ―Rate of biodegradation of crude lowered. After oxidation the values of flash point and fire oil by micro-organisms isolated from oil sludge environment,‖ African Journal of biotechnology, vol. 7 (24) point has marginal decrease. 17 December, pp 4495- 4499, 2008. IV. CONCLUSION [11] E. O. Aluyor, M. Ori-jesu, ―Biodegradation of mineral oils— A review,‖ Afr. J. Biotechnol., vol. 8, pp. 915-920, 2009. Crude pongamia oil shows better performance with [12] Bertrand. Y and Hoang. L. C. ―Vegetable oils as substitute regard to flash and fire point, electric strength values when for Mineral insulating oil (MIO)s in medium voltage compared to mineral oil and very poor performance with equipments,‖ EDF R&D, Electrical Equipment Department respect to acidity, dielectric dissipation factor, resistivity CIGRE, session, D1- 202. 2004 characteristics. Qualities of pongamia oil can be improved [13] Stockton David P, John R . Bland J. R. Todd Mcclanahan, by adopting physic-chemical treatment process. The treated ―Seed oil based coolants for transformers,‖ IEEE Industry oil has shown improvements with respect to all parameter Application magazine, January/February. pp 68-74, 2009. but decreases of flash point and fire point also the [14] IEC 60296,‗Fluids for electrotechnical applications - Unused temperature difference between flash point and fire point is Mineral insulating oil (MIO) for transformers and decreased. The performance of electrical properties is switchgear‘ International Electrotechnical Commission, 2012. improved by both processing methods. Performance of [15] Scott, P.T., Pregelj, L., Chen, N. et al.,―Pongamia pinnata: oxidized oil shows deteriorated values. The processing An Untapped Resource for the Biofuels Industry of the methods are however needs further improvements or by Future ‖ Bioenerg. Res., vol.1, Issue 1, pp 2–11, 2008. alternative methods to meet the requirements of IEC 62770. [16] Savita Sangwan, D.V.Rao and R.A. Sharma, A Review on ACKNOWLEDGMENT Pongamia Pinnata (L.) Pierre: A Great Versatile Leguminous Plant, Nature and Science, vol. 8, issue:11,pp 130-139, 2010. The authors are thankful to the management of CPRI, [17] Gaurav Dwivedi n, M.P.Sharma, Gaurav Dwived in, Bengaluru and JSSRF Mysore for the support and M.P.Sharma, ―Prospects of biodiesel from Pongamia,‖ in encouragement India, Renewable and Sustainable Energy Reviews 32, pp. 114–122, 2014. REFERENCES [18] Bobade S.N.1 and Khyade V.B.2, ―Detail study on the Properties of Pongamia Pinnata (Karanja) for the Production [1] W. Ziomek, ―Transformer Electrical Insulation [Editorial],‖ of Biofuel‖, Res.J.Chem.Sci, vol. 2(7), 16-20, July 2012. IEEE Trans. Dielectr. Electr. Insul.,vol. 19, pp. 1841-1842, [19] Jiri Cmolík,―Physical refining of edible oils,‖ European 2012. Journal of Lipid Science and Technology, Volume 102, Issue [2] M. Heathcote, J & P Transformer Book, Thirteenth ed. 7, pp. 472–486, 2000. Burlington: Newnes, 2011. [20] K. G. Devi, M. Ravindran and S. S. Kumar, ―Analysis of [3] Sanka Sen., BHEL, Tata McGraw-Hill Education, pp. 34-47, critical parameters of vegetable oil as an alternate dielectric 2003. fluid to mineral oil,‖ 10th International Conference on [4] J. Singh, Y. R. Sood, R. K. Jarial, and P. Verma, ―Condition Intelligent Systems and Control (ISCO), Coimbatore, pp. 1- Monitoring of Power Transformers-Bibliography Survey,‖ 5, 2016. IEEE Electr. Insul. Mag., vol. 24, no. 3, pp 11-25, 2008. [21] D. M. Mehta, P. Kundu, A. Chowdhury, V. K. Lakhiani and [5] Saurabh Vishal, Vikas, Prashant, ―Transformer's History and A. S. Jhala, ―A review of critical evaluation of natural ester its Insulating oil,‖ 5th Nat. Conf. INDIA Com Computing For vis-a-vis mineral oil insulating liquid for use in transformers: Nation Development, pp. 1-4, 2011.

528 | IJREAMV04I0844075 DOI : 10.18231/2454-9150.2018.1134 © 2018, IJREAM All Rights Reserved. International Journal for Research in Engineering Application & Management (IJREAM) ISSN : 2454-9150 Vol-04, Issue-08, Nov 2018

Part II,‖ in IEEE Transactions on Dielectrics and Electrical [36] ISO 3104, ―Test method for kinematic and dynamic Insulation, vol. 23, no. 3, June, pp. 1705-1712, 2016. viscosity of Petroleum products‖, International [22] K. G. Devi, M. Ravindran and S. S. Kumar, ―Analysis of Organization for Standardization.1994. critical parameters of vegetable oil as an alternate dielectric [37] , ISO 3016, ―Test method for kinematic and dynamic fluid to mineral oil,‖10th International Conference on viscosity of Petroleum products,‖ International Intelligent Systems and Control (ISCO), Coimbatore, pp. 1-5, Organization for Standardization.3016. 2016. [38] ASTM D971 (2012), ―Standard Test Method for Interfacial [23] Hilary I. Inyang Life Kaanagbara, ―Modelling oil tension,‖ American Standards Institution,2012. degradation in electric transformer oil under typical loads,‖ : [39] IEC : 60814, Determination of water by automatic International Journal of Global Energy, Inderscience coulometric Karl Fischer titration of Insulating liquids - Oil- publications. Issues 2007 - vol. 28, No.2/3, pp. 325 – 343, impregnated paper and pressboard,‖ International 2007. Electrotechnical Commission,1997. [24] IS 1866, ―Code of Practice for Electrical Maintenance and [40] IEC 62021-2,―Determination of Total acidity‘. International Supervision of Mineral insulating oil(MIO) in Equipment,‖ Electrotechnical Commission,‖,2004. Bureau of Indian Standards, (BIS),‖ 2000. [41] ISO 2592, ―Determination of flash and fire points Cleveland [25] IEC:60422, ―Mineral insulating oil(MIO) s in electrical open cup method,‖, International Organization for equipment - Supervision and maintenance guidance Standardization. 2000. International Electro technical Commission, 2005. [42] IEC 61125 -1992 ―Determination of Total acidity,‖ [26] M. Srinivasan, S. Paramasivam, A. Krishnan, ―Low cost International Electrotechnical Commission,1992 digital measurement system for determination of temperature [43] I.Hosier, J. Gu, W. Chotchuangchutchavel, A. Vaughan, rise in dry type transformer,‖ Int. J. Instrumentation ―Effect of viscosity and water content on the breakdown Technology, Inderscience Enterprises Ltd. vol. 1, No. 1, pp strength of vegetable oils,” IEEE Int'l. Conf. Dielect. Liquids 72-83, 2011. (ICDL), pp. 1-4, 2014. [27] Ruijin Lio, Jian Hao, George Chen Zhiqin Ma, Lijun Yang, [44] Shah Z.H and Tahir.Q. A, ―Dielectric Properties of Vegetable ―A comparative Study of Physicochemical, Dielectric and Oils, Dielectric Properties of Vegetable Oils,” Journal. Sci. thermal properties of pressboard insulation impregnated with Res. 3 (3), pp.481- 492, 2011. natural ester and mineral oil,‖ IEEE transactions on [45] S. Tenbohlen, D. Vukovic, J. Hathun, S. Barker, R. dielectrics and electrical Insulation, vol 18, No 5 October , Frotscher, ―Application of vegetable oil-based insulating pp 1626 -1637, 2011. fluids to hermetically sealed power transformers,‖ Paris, [28] Santanu Singha, Roberto Asano Jr., George Frimpong, C. France:Cigre, pp. A2-102, 2008. Clair Claiborne, Don Cherry, ‗Comparative Aging [46] S.Rakesh, Joy Thomas, ―Pongamia oil, an eco-friendly Characteristics between a High Oleic Natural Ester Dielectric alternative for mineral oil used in high voltage transformer, Liquid and Mineral Oil‘, Transactions on Dielectrics and Dielectrics (ICD),‖ IEEE International Conference on, 3-7 Electrical Insulation, IEEE, on J., vol 21,Issue 1,pp. 149- July 2016. 158,2014. [29] M. A. G. Martins and A. R. Gomes, ―Comparative study of the thermal degradation of synthetic and natural esters and mineral oil: effect of oil type in the thermal degradation of insulating kraft paper,‖ in IEEE Electrical Insulation Magazine, vol. 28, no. 2, March-April, pp. 22-28, 2012. [30] IS:335, ―Product specification for New insulating oils,‖ Bureau of Indian Standards,‖ (BIS) 1993. [31] ASTM D6871 - 03, ―Standard for specification for natural (vegetable oil) ester fluids used in electrical apparatus,‖ American standards institution,2003. [32] IEC:62770 ―Fluids for electrotechnical applications - Unused natural esters for transformers and similar electrical equipment,‖ International Electrotechnical Commission, 2013. [33] IEC 60156 ―Determination of the breakdown voltage at power frequency - Test method for, Insulating liquids,‖1995. [34] IEC 60247 ―Measurement of relative permittivity, dielectric dissipation factor (tan delta) and d.c. resistivity Insulating liquids,‖ International Electrotechnical Commission, 2004. [35] ISO 3675 , ―Test Method for determination of crude petroleum and liquid petroleum products of density or relative density Hydrometer method, International standards,‖ Organization International standards Organization,1992.